Existing computing devices employ various authentication techniques, which prevent unauthorized use of such devices and/or prevent unauthorized access to certain functions of such devices.
For example, a mobile phone may automatically enter a locked mode, where use of the phone is restricted, when the phone is not in use. A user may therefore be required to enter a password or passcode to unlock the phone. For example, the user may be presented with a 10-digit PIN number pad via which the user can enter a numeric passcode. On many current mobile phones, for instance, the user may be required to enter a predetermined four-digit number to unlock the phone.